# Why does values of CP differ from CV?

## Why does values of CP differ from CV?

Cp and Cv of one solid have one fixed value and different for different solids.. Cp and Cv of one liquid have one fixed value because all liquids have fixed volume and has no effect of pressure. A gas has a different value of cp and cv because volume is affected by pressure. VALUES ARE AT 20 C.

Is water vapor an ideal gas?

At elevated temperatures, and low pressures, water can be gaseous; in fact, water always has a vapour pressure. The answer to your question is thus NO. Sometimes, the behaviour of water vapour can approximate the behaviour of an ideal gas.

Why can you use the ideal gas law for water vapor?

Yes, for many practical purposes, you may use the ideal gas law also as an approximation for water vapour. The ideal gas law does not give you a value for the second quantity. For example, assuming equilibrium conditions for saturated steam at a temperature of T=298.00 K, the corresponding pressure is p=3141.7 Pa.

### Is vapor a gas or liquid?

A vapor refers to a gas-phase material that that normally exists as a liquid or solid under a given set of conditions. As long as the temperature is below a certain point (the critical temperature; this varies for each substance), the vapor can be condensed into a liquid or solid with the application of pressure.